A femtocell performs many of the function of a Node B, but is optimized for deployment in the indoor premises and small coverage public hotspots.
Security Gateway (SeGW) - Installed in an operator’s network, the Security Gateway establishes IPsec tunnels with HNBs using IKEv2 signaling for IPsec tunnel management.
IPsec tunnels are responsible for delivering all voice, messaging and packet data services between HNB and the core network.
HNB Gateway (HNB-GW) - Installed within an operator’s network, the HNB Gateway aggregates traffic from a large number of HNBs back into an existing core service network through the standard Iu-cs and Iu-ps interfaces.
The Iu-h interface also defines an efficient, reliable method for transporting Iu-based traffic as well as a new protocol (HNBAP) for enabling highly scalable ad hoc HNB deployment.